The long-term goal of this project is the improved prescription and design of interface liner materials for patients with limb amputation so as to create prostheses that are mechanically stable and resist soft tissue injury during ambulation. The specific aims are to develop a suite of testing systems to evaluate commercially available interface liners, interpret the results, and communicate to practitioners how these different liners affect skin mechanics, limb- socket stability, and limb temperature. The developed suite should quickly and easily allow practitioners to evaluate materials for use with their patients and assist them in making informed decisions based upon the best available scientific evidence and mechanical testing data. Key features include properties of new prosthetic liners and to what degree the liners change their mechanical performance over time with continual and typical use. These material performance data are placed within a clinically relevant framework for evaluation and prescription. Further, development of this suite will allow continued provision of this service at a low cost well beyond the funding period. To achieve the aims, custom instrumentation is developed to test liners specifically for limb prosthetics application. The materials are tested for their abilities to provide: cushioning;prosthetic suspension;skin adherence;volume change accommodation;breathability;thermal conductivity;and durability. Both new liners and those used by patients for up to nine months are tested. Both conventional liners and "smart" liners, which change their properties upon an applied voltage or force, are tested. Biomechanical models are implemented to compare limb-socket interface mechanics, limb-socket stability, and thermal stresses on the residual limb for different liners during patient use. The data are then incorporated into a clear and easy-to- understand format presentation for use by practitioners, patients, researchers, and industry. The health relatedness of this application is an evaluation and dissemination strategy that has widespread use in rehabilitation treatment. Quantitative material data are presented in a clinically relevant format to improve amputee patient care and health-related quality of life. Liner selection and prescription should be enhanced, reducing the occurrence of skin breakdown and injury to persons with limb amputation. Further, this research will help to specify quantitative engineering needs of future liners. Potentially, the efforts described in the proposed application can be extended to other areas where the selection of the skin interface is of clinical importance, including wheelchair seating, footwear, insoles and orthotic devices. PUBLIC HEALTH RELEVANCE: The long-term goal of this project is a useful tool for prescription of interface liner materials for patients with limb amputation so as to create prostheses that are mechanically stable during ambulation and do not cause soft tissue injury.